Death to release windows
The key point of the deal is this: 2929 will release the films simultaneously to theatres, home video, and their HDNet high-definition cable/satellite channels. Clearly, they don't feel like release windows matter anymore - and I think they're right.
We're already living in an era where consumer choice is the dominant factor - not the producer's will. (Here, I'm using 'producer' in a broader way, not to mean 'film producer.') Consumers will choose the way they want to see a first-run film: at home, or in the theatre, or while traveling, on a laptop or mobile device. Cuban and Wagner want to prove this can make economic sense - perhaps by driving up consumer demand for their HDNet channels, or through pay-per-view. Another way that simultaneous release helps is by consolidating marketing costs into a shorter time frame, rather than stringing them out to support multiple release windows.
But studios like release windows, and they won't let go easily. For two reasons. One, they're comfortable with understanding the range of revenues that a given film will generate in each window (theatrical, home video, in-flight, etc); mashing things into a simultaneous release is scary and experimental. Two, they've got different business groups to support each window - and those guys don't always play nice together.
But if 2929 can prove that simultaneous release - I actually prefer the term 'synchronized distribution' - makes business sense, and consumers start demanding it, change will happen.